The disclosed embodiments generally relate to the field of fluoropolymers, and to the preparation and use of fluoroaromatic polymers. Fluoroaromatic polymers may be crosslinked to give an elastomeric material that may be useful for applications, such as, for example, applying a top layer coating onto an electrostatographic component such as a roll or belt used in printing and copying operations. An example is an outer coating for a fuser roller or fuser belt. Such crosslinked fluoroaromatic polymers may be useful in non-porous applications.
U.S. Pat. No. 7,127,205, which is hereby incorporated by reference in its entirety, provides a process for providing an elastomer surface on a fusing system member. Generally, the process includes forming a solvent solution/dispersion by mixing a fluoroelastomer dissolved in a solvent such as methyl ethyl ketone and methyl isobutyl ketone, a dehydrofluorinating agent such as a base, for example the basic metal oxides, MgO and/or Ca(OH)2, and a nucleophilic curing agent such as VC-50 which incorporates an accelerator and a crosslinking agent, and coating the solvent solution/dispersion onto the substrate. Commonly used fluoropolymer crosslinkers are bisphenol-A and bisphenol AF that are known to react with unsaturated positions on fluoropolymer chains. The surface is then stepwise heat cured. Prior to the stepwise heat curing, ball milling is usually performed for from 2 to 24 hours.
A new material system for fusing or for other applications is desired that exhibits improved mechanical properties such as wear, and modified surface interactions to improve release and reduce or eliminate the use of fuser oil or other oil materials in other applications. Improving these properties would extend life of the component. Aliphatic-aromatic fluoropolymers incorporate the heat resistance and release properties of fluoropolymers, with the high modulus of stiff aromatic ring components and the flexibility of aliphatic chain components, whereby modifying ratios of the two components can be used to tailor properties. The mixed aliphatic-aromatic fluoropolymers contain a crosslinkable component and can be crosslinked using nucleophilic crosslinking agents. This results in elastomeric character of the material, and mechanical robustness.
In addition, an improved method of crosslinking polymeric materials, such as aromatic compositions, and especially fluoroaromatic compositions, to produce strong and robust polymer coatings for various applications is desired. U.S. Pat. No. 6,313,185 discloses a method of crosslinking nanoporous materials using diene and dienophile backbones is disclosed.
However, an improved method of crosslinking of aromatic compositions, and specifically, fluoroaromatic compositions is desired. An improved method for crosslinking aromatic compositions to be useful in non-porous polymeric applications is also desired. Enclosed herein is a crosslinking method that can be carried out under air ambient conditions using common, commercially available nucleophilic crosslinking agents. Ease of processing can be improved, and the cost reduced as compared with air sensitive crosslinking methods such as peroxide induced crosslinking.